The terminal box (or terminal block) is a type of functional module commonly used in the industry, in particular in forming a control system that includes a plurality of terminal boxes. A terminal box generally provides a casing and one or more circuit boards enclosed therein, to form one or multiple functional module. Each functional module is connected to a particular working machine, to control the operations of the working machine. In a factory, dozens to hundreds of working machines may be used, and each working machine may be connected to one or more functional modules. These functional modules combine into one system, referred to as a control system. In such a control system, the main function of the terminal boxes is to provide horizontal communication between/among functional modules. That is, to provide transmission of electrical power, data, and control signals between/among different functional modules.
The connections between/among terminal boxes are realized by electrical contacts provided on the casing, that allow electrical power, data and signals to travel between two functional boxes. The known technology also provides a photo Transceiver module for optical communication between a functional module in one terminal box and a functional module in another terminal box. To simplify the connection and communication between/among terminal boxes in a system, the known art also provides a longitudinal support rail, to which a plurality of terminal boxes can be affixed, using the clamping mechanism provided at the bottom of the terminal boxes. The support rail allows the terminal boxes to align closely one adjacent to another, so that the electrical contacts on the sides of the terminal boxes form a reliable connection. US Patent Publication No. US 2013/237067A1 discloses a “Data bus structure for terminal blocks and terminal blocks using the same,” that further provide a bus structure in the support rail, whereby the plurality of terminal boxes can share power, data, and control signals via the bus structure.
The conventional terminal box provides electrical contacts for power lines, data lines, and signal lines electrical contacts on the box body. There are two groups of electrical contacts provided on each box body, which are respectively arranged on both sides of the box body, symmetrically with each other. When all functional modules are arranged in series, for example, aligned side-by-side on the above-mentioned support rail, the electrical contacts on one side of a specific terminal box will contact the electrical contacts on the corresponding side of an adjacent other terminal box of the side. The electrical contacts on the other side are in turn connected to the electrical contacts on the corresponding side of a third terminal box immediately adjacent to that other side. In order to ensure the formation and stability of the electrical connection, conventional terminal boxes are still required to provide engaging devices so that adjacent two terminal boxes can abut against each other without relative movements. A typical design of such a terminal box can be found in U.S. Pat. No. 5,716,241, title: I/O Device for Data Bus. Connectors that provide contacts in such terminal boxes are commonly referred to as T-shaped electrical terminals, such as those shown in U.S. Pat. No. 7,704,079, title: T-Shaped Shielded Bus Connector. In this connection, all the terminal boxes essentially form a series connection. The lines formed by the concatenation are a “bus;” power, signals, etc. that pass through the lines can be shared by all the terminal boxes.
A control system includes a plurality of terminal boxes. In terms of control, each terminal box can be considered a functional module, although each terminal box may functionally include multiple functional modules. The control system must address or readdress each functional module, i.e. each terminal box, before operation. In other words, before the control system starts to operate, the address or address code of each terminal box (hereinafter collectively referred to as “address”) must be assigned or reassigned by a controller or control module, which is usually one of the terminal boxes.
However, terminal boxes currently used in the industry do not usually provide automatic addressing functions. When addressing the terminal boxes of a control system, usually an addressing tool is used to generate a unique address as the “default address” of each terminal box and to write it into the functional module of the terminal box. The address written in is identified as the address of the terminal box during operations thereafter. Another method is the manual addressing. For example, a dip switch is provided on the terminal box for addressing. After the terminal box is placed on a support rail, a number or code is generated according to a certain rule and assigned to the terminal box, as its address at the time of operation.
In U.S. Patent Publication 2004/195078, title: Integrated Conveyor Bed, a method of giving automatic addressing to a concatenated control module is proposed. According to the method, the master module first issues a start signal to the first of the plurality of control modules connected by the “daisy chain.” After the first control module returns a response signal, the control module sends a unique communication address assigned to the first control module. Thereafter, the first control sends a start signal to the second control module on the downstream side. The master module sends another unique communication address in response to the response signal. The above addressing operation is repeated until all the control modules of the system have been assigned their communication addresses.
U.S. Patent Publication 2016/318714, title: “Method for Addressing/Sequencing Linearly Interlinked Control Components of a Conveying System” provides an improved automatic addressing method. The method includes addressing by a control module to each downstream control module on one direction and addressing each downstream control module in the opposite direction, followed by addressing by a downstream control module in one of the directions in a reversed sequence. The resulted addresses are used as the addresses of all control modules. The method obtains the physical location information of each control module through this process.
A method and apparatus for identifying spatial proximity in a modular system is disclosed in U.S. Pat. No. 10,177,961. The invention provides a method for addressing a control system containing a plurality of functional modules, comprising: requesting all functional modules to open their photo transmitters (S) and photo receivers (R); receiving status signal of the photo receivers from all functional modules through a communication network; assigning a starting address to the functional module that does not receive an optical signal; turning on the photo transmitter of the functional module that just receives an address assignment; assigning a next address to the functional module that receives the optical signal; repeating the above steps until all functional modules have been assigned an address. A disadvantage of this invention is that it can only be applied to systems in which the functional modules are already correctly aligned. Yet another disadvantage is in that all functional modules need to have a locational address, before they can be addressed.
Taiwan Patent Application No. 107108158 proposes a control system comprising a plurality of functional modules and an addressing method for addressing functional modules thereof. The invention provides an addressing structure and method for assigning functional modules in a control system based on optical signals. The invention facilitates the user to address or readdress a system, when one functional module is removed from or added into the system. The system provides a support rail to ensure that all functional modules are aligned side by side and that their light transceivers are properly aligned. The addressing method comprises the following steps: The control module sends an addressing command to an adjacent functional module in one direction and an address signal to a communication network connected by all the functional modules. The functional module receiving the addressing command picks up the address, uses it as its own address, and sends an addressing command to its adjacent downstream functional module. The control module sends a next address signal. Repeat the above steps until the addressing is completed.
Taiwan Patent Application No. 107108158 ensures all functional modules are aligned relatively to each other and their optical transceivers are correctly aligned, mainly because the functional modules are affixed to the support rail side-by-side. However, in such a system, sometimes a light emitter can not align to its corresponding receiver, due to, for example, malfunction of the light emitter or receiver. In such a case, the addressing operation cannot be accomplished.
When an addressing operation is interrupted for any reason, it is preferable that the system can readdress or resume the addressing, in addition to simply dragonize reasons of the interruption. Unfortunately, the conventional art does not provide such a solution.